Every day, thousands of tonnes of petroleum-derived plastic waste accumulate in the environment, leading to an increasing number of landfill sites for non-biodegradable waste and escalation of the costs of waste disposal.
One solution to this problem is to use biodegradable alternatives to these plastics, one of which is the production of polyhydroxyalkanoates (PHA), a class of high-performance biodegradable polymers.
PHAs can be produced commercially in processes of intracellular storage (reserves) carried out by microorganisms using a suitable substrate (in particular a sugar or an organic acid). However, the cost of the PHAs thus obtained is well above that of the petroleum-derived plastics, in particular because of the strict environmental controls required and the sterile operating conditions required for controlling the production operation.
Moreover, PHAs do not always have the necessary physical characteristics for specific industrial applications, in particular glass transition temperature (Tg) or transparency.
Haloferax is a genus of Archaea belonging to the phylum Euryarchaeota and to the order Halobacteriales. The cells of Haloferax are pleomorphic motile rods or flattened disks, and are strict aerobes. They are hyperhalophilic organisms.
Certain species of Haloferax produce biopolymers. In particular, Haloferax mediterranei produces PHA (Lillo et al. Appl. Environ. Microb. 56:2517-2521, 1990).
However, Lillo et al. describe that Haloferax mediterranei only produces PHA under conditions of stress, from starch or glucose, and not from other carbon-containing substrates such as oils, triglycerides, fatty acids or glycerol.